Voters with unused polling cards made their way to Mr Clegg’s house to protest, claiming that up to 200 people at one polling station had been turned away, not including those who saw the queue and left.

One woman voter said: “It has been inadequately manned, there was hardly anyone there.”

A male elector said: “We have people dying in Afghanistan to give the Afghans the vote and here they have closed the polls and lots and lots of people have been disfranchised.”

Another man outside Mr Clegg’s house said: “I have been robbed of my right to vote.”

The deputy prime minister, Harriet Harman, said the complaints should be a matter for the Electoral Commission.

“I am concerned that everybody who had turned up to vote before 10 o’clock should have their vote cast,” she said.

“As I left my constituency I could see the lights on in one polling station but people still queueing outside and that was just a few minutes before 10.

“We have to make sure that all those votes are counted.”

There were also reports of voters being turned away in Manchester, Liverpool, Leeds and London.

In some cases local polling stations were said to have run out of ballot papers, while in others they were unable to get all those who wanted to vote into booths in time.

The problems arose despite polls being open for 15 hours from 7am until 10pm, suggesting that turnout would be far higher than in recent elections.

Some voters vented their frustration on the social networking website Twitter, where Paul Hodgson wrote: “Wife had to queue for 50 minutes to vote because of vast turnout. Loads of students too.” Later he added: “Queue for polling station is massive and it’s pouring. We can’t vote … Hundreds left outside too. Cops are here. It’s kicking off.”

In Swindon, Steven Taylor, a returning officer, said: “Cars have been queueing, people were standing in queues 140 people long in some places.

“We are hoping that now 10pm has come, everybody queueing has been able to vote.”

Experts predicted that the turnout was expected to have hit the highest level since the Labour landslide of 1997.

The proportion of people voting was thought unlikely to have approached the record levels set in the 1970s because of Labour’s problems in persuading its core supporters to vote in its safe constituencies.

But experts said turnout was expected to hit the levels which led to Labour’s victory 13 years ago, when 71 per cent of the electorate went to the polls.